1. Field
The present invention relates generally to communications. More particularly, in aspects the invention relates to adaptation of wireless communication parameters based on interference.
2. Background
A modern communication system is expected to provide reliable data transmission for a variety of applications, such as voice and data applications. In a point-to-multipoint communications context, known communication systems are based on frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), time division duplexing (TDD), and perhaps other multiple access communication schemes.
A CDMA system may be designed to support one or more CDMA standards, such as (1) the “TIA/EIA-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System” (this standard with its enhanced revisions A and B may be referred to as the “IS-95 standard” ), (2) the “TIA/EIA-98-C Recommended Minimum Standard for Dual-Mode Wideband Spread Spectrum Cellular Mobile Station” (the “IS-98 standard”), (3) the standard sponsored by a consortium named “3rd Generation Partnership Project” (3GPP) and embodied in a set of documents known as the “W-CDMA standard,” (4) the standard sponsored by a consortium named “3rd Generation Partnership Project 2” (3GPP2) and embodied in a set of documents including “TR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum Systems,” the “C.S0005-A Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems,” and the “TIA/EIA/IS-856 cdma2000 High Rate Packet Data Air Interface Specification” (the “cdma2000 standard” collectively), (5) the 1xEV-DO standard, and (6) certain other standards.
Portability and functionality of wireless communication devices continue to improve, contributing to the proliferation of wireless communication networks. Many conventionally-wired connections are being replaced with wireless connections, including ad hoc connections made when one wireless device moves into the connectivity area of another wireless device. Of some interest are wireless local area networks (wireless LANs or WLANs), such as wireless networks under the various IEEE 802.11 standards. Of some interest are also wireless personal area networks (wireless PANs or WPANs), which networks are often used for communication between or among devices close to one person. Wireless PAN technologies typically have a reach of about ten meters, and may include Bluetooth® devices, ZigBee® (IEEE 802.15.4 standard) devices, ultra-wide band (wireless USB or UWB) devices, and various remote controls. WPAN rates of data transfer currently range up to 480 Mbps for UWB technology specified in ECMA-368, with further enhancements possible to achieve rates of 1 Gbps and higher.
Common wireless LAN technology is often referred to as “WiFi,” and operates under the IEEE standard 802.11a/b/g. Such WLAN networks typically operate over a range of approximately fifty meters, and provide data rates of 54 Mbps for IEEE 802.11a and 802.11g. The emerging IEEE 802.11n standard may improve the data rates to 600 Mbps.
A wireless LAN or PAN network may be used for communications between or among personal devices, or for communications between such personal devices and access points providing other resources, such as gateways to additional networks, including cellular networks and the Internet.
Wireless body area networks (WBANs) may be considered a subset of personal area networks. A wireless body area network may include wireless sensors for monitoring various body parameters and functions. The sensors may transmit real-time data to a base station located, for example, in a person's home. Typical range of WBANs is about three meters.
A wireless network can be constructed using solely peer-to-peer communications, without access points. Further, wireless networks can include both access points (infrastructure mode) and peer-to-peer communications. (These types of networks may be referred to as ad hoc networks). Ad hoc networks can be self-configuring with independent discovery of devices by other devices. For example, when a mobile device (or access point) receives communication from another mobile device, the other mobile device may be added to the network. As the mobile devices leave the area, they may be dynamically removed from the network. Thus, the topography of the network can be constantly changing. In a “multihop” topology, a transmission may be transferred through a number of hops or segments, rather than directly from a sender to a recipient. Multihop topology need not exclude direct device-to-device communications.
WiMedia Ultra-Wideband (UWB) as promulgated by ECMA International in Standard ECMA-368, “High Rate Ultra Wideband PHY and MAC Standard” (December 2005) describes a common radio platform distributed medium-access technique that provides a solution to operating different wireless applications within the same network. The WiMedia UWB common radio platform incorporates media access control (MAC) layer and physical (PHY) layer specifications based on multi-band orthogonal frequency-division multiplexing (MB-OFDM). The WiMedia MAC and PHY specifications are intentionally designed to adapt to various requirements set by international regulatory bodies. Manufacturers needing to meet regulations in various countries can thus do so relatively easily and cost-effectively. Some other application-friendly features that WiMedia UWB attempts to implement include reduced level of complexity per node, long battery life, support of multiple power management modes and higher spatial capacity.
WiMedia UWB-compliant receivers may need to cope with interference from existing wireless services while providing large operational bandwidth. At the same time, such receivers typically perform with relatively low transmit power.
UWB systems may be designed to operate in an unlicensed part of spectrum using transmit equivalent or effective isotropic radiated power (EIRP) of −41.3 dBm/MHz, and a bandwidth of 500 MHz or more. Such a large spectral occupancy increases the likelihood of some interference falling into the UWB receiver bandwidth. At the same time, the low transmit EIRP limits the communication range and provides little link margin to deal with the interference. To enable the UWB receiver to continue to provide the desired user experience (latency and/or throughput) in the presence of in-band interference, having some form of interference mitigation is desirable.
An interferer may be any other device that runs different applications (e.g., WiMax and future wireless systems) and transmits signals in the same electromagnetic frequency band as the UWB receiver. Interference can also be self-generated within the platform where the UWB receiver resides. In multi-mode handsets or laptops, for example, harmonics, spurious emissions, clocks, and similar signals generated by other radios could fall within the UWB band.
A need exists for apparatus, methods, and articles of manufacture that improve reliability of wireless communications in the presence of interference, particularly within wideband wireless networks .A need also exists in the art for apparatus, methods, and articles of manufacture that reduce transmissions created by wireless device that constitute interference for other wireless devices, particularly in wideband networks including wireless LANS and wireless PANs. A need further exists for apparatus, methods, and articles of manufacture that reduce power consumption of wireless devices.